Fifty to two hunded of thus shaped side walls are supplied as a unit and stacked together according to the prior art, and a bottom plate formed by the prior art is inserted, then the side wall and the bottom plate are joined by a pasting or the like as a finished cup. This method and apparatus can also be used for making a cup using a blank previously cut into a fan shaped configuration. Heretofore, a side wall of the cup has been formed by using a cup side wall shaping machine as illustrating by FIG. 12. This side wall shaping machine is composed of a pair of wings 9 and 9' capable of being moved slightly upwards and downwards about a connecting pin 7 along the groove 8, a pair of swingable pin 15 and 15 are disposed at the outer side portions between the outer ends of swingably movable end and the inner end movable around the connecting pin 7, the swingable pins 15 are also placed at each of the two top points of the operating rods 30 and 30; A slider 20 and an urging rod which urges these wings 9 upwards and downwards as a whole and moves the urging rod 6 disposed at the upward end of the connecting rod 21 to move the blank 1 is mounted between the end connected by the pin 7 and the other free end, swingable pins 15 are opened or closed by the operating rod 21 and a slider 20 which pushes the blank 1 against a frusto-conical shape, hereafter it can be referred only to a cone roll or a cone 4; Operating rods 30 which push said pair of wings 9 and 9' to open or close in a harmonized manner:
As rolled paper for making the cups is cut into each fan shaped size as a blank and is supplied to a side wall shaping machine not shown. Next, the blank 1 supplied to the lower face of the cone roll 4 is further pushed by a pusher member 6, then the blank is further pushed between the two inner faces 22 of each of the swings 9 having the same convexed face as the concaved outer face of cone roll 4 and is further clamped between two faces and is further sealed as a frusto-conical cup. Then wings 9 and 9' are opened to send the completed cup having thus shaped frusto-conical shape to its axially small diameter side and the next blank to be worked as a next cup is set ready for supplying to the lower part of said cone roll 4 and thus one cycle can be finished.
Sealing of the Pasting Portion of the Formed Cup
Heretofore, a sealing of a formed cup has been conducted using a sealing agent noted below. As a sealing agents there are three kinds of sealing agents, such as, glue seal, hot-melt seal, heat seal of laminated hot melt seal, and these method using three kinds of sealing will be explained hereafter.
Glue Sealing
Glue is a water solution of alpha (.alpha.) starch. Since it is applied before it is sealed and is dried in natural air at the time for drying and solidifying and this differs depend upon the concentration thereof and requires some extent of drying, and therefore the capacity of cup making is restricted by the kind of glue to be used.
Hot Melt Seal
Since the interfacial tension of the thermally plastic resinous material to the paper is small, therefore such kind of glue is used which is liable to adhere to the paper and having strong adhesion power to the paper after cooling. In order to make easier the sealing operation, several kinds of synthetic resinous materials are selected to mix them to lower the thermal fusion temperature and to increase the sealing strength. For example, polyethylene having high adhesion force at about 120.degree. C. to the paper, and paraffin having lower adhesion force having thermally softening temperature of 60-80.degree. C. are selected to mix them to satisfy the required sealing agents. Generally, sealing agents formed as pellet shape or as a string shape is fused into liquid state by using fusing apparatus attached to the gun and applied to a portion by means of springs or compressed air.
Heat Sealing by Means of Laminated Polyethylene
This sealing agent is made on a mass production scale by using an equipment as mentioned below, so it is able to apply a thin film of polyethylene over the entire surface of the paper material of the cup. FIGS. 13(A) and (B) depict a side view and a front view of the production equipment of the polyethylene paper, and there is a rolled polyethylene laminated paper is supplied on the upper surface thereof fused thin film of polyethylene 63 by an electro-thermal fuser 64 named as a T die disposed above it when it passes through a polyethylene extender 62 consisting of a pair of rolls 62a and 62b spaced parallel at a desired spacing. The paper 61 covered with a thin film of fused polyethylene film 63 are fed as a one body of polyethylene adhered film 65 and is wound around a winding roll 66 disposed around down stream side. In this manner, if a paper adhered with polyethylene film of 15 .mu. (micron) is heated for adhesion, then polyethylene is melted and a seal where polyethylene is confronting face to face with each other would be made consolidated, however, these bodies will immediately solidify upon removal of heat source. For papers of general purpose use which is not covered with coating agent for increasing their printing effects or with aluminum foil bonding for improving decoration effects, is required to place such adhesion improving agents. For compacting sealing or overlapped type sealing, polyethylene which solidifies upon removal of heat source is used for adhesion.
Properties of Each of the Sealing Agents
1)Heat Resistant Property
If the cake is worked above 150.degree. C., glue only is selected. For the cake of steamed type both a glue and a polyethylene laminated paper (120.degree. C.) are used and it is determined that whether they should be used depends on the quantity of the paraffin to be used.
2) Water Proofing Property
Since polyethylene is strong in water proofing property, it can be used for cups for storing drinks and hot melted raw material is strong enough for storing water, however, from the view point of its price it is impossible to cover all the surface of the paper. Glue is poor in water resistancy.
3)Workability of Coating and Sealing
Polyethylene&gt;Glue&gt;Hot melt
4) Prices
Glue is lowest and hot melt is most expensive while polyethylene is placed between the two.
(1) Shaping of the Side Wall and the Apparatus to be Used for
As already mentioned, a pair of wings and a pair of cone rolls are combined together for utilizing an up and down motion and right and left wing motion to make paper for cups, which is lower in strength and is liable to be broken more easy as compared with metal plates, to wind up around a cone roll using reciprocating open and shut down motion. There is a limit for repeating opening and shutting motion and there is a need to feed a paper for cups to be supplied previously formed and cut as a fan shaped blank. So it has been desired that a method and an apparatus for making side walls of paper cups with higher speed can be provided, because the former apparatus have drawbacks that they were poor in high speed operation, complicated construction, high wear ratio and poor in productibility. Upto the present, if the cup is top sealed type as for the cone cup of ice cream, it has been possible to make a cup by winding a cup around the outer surface of the cone rolls and blowing air from the large diameter opening side after the cup has been sealed. However, normally the side walls of the paper made cup for cakes is formed its small diameter side cut as hollow frusto-conical bottomless shape, so if one tries to blow air to transport it to another place the wind only passes through the interior of the cup and is not enough to act as a force to transport it. If one makes a frusto-conical shaped cup with a cone roll type apparatus, he cannot propel it to a next portion and receive the next blank to be formed there, that is, feeding of paper, forming it to a cup, removal of the formed cup and feeding of the next blank were not continuously repeated, and these reasons have prevented from high speed production of frusto-conical cup side walls using rotating cone rolls.
1) Sealing by Glue
When supplying sealing agent to a paper to be sealed, it is considered very easy since, due to natural air drying, no heating or pressurising, once glue is applied to the paper it only requires some length of time for evaporating its water content, in addition, if it becomes fully dried by heating the adhesive force may be lost, so it is necessary that a slight extent of water is kept retained. Depending on some working condition, artificial heating may be used. Adhesion of pasting portion must be considered carefully as to how to carry out the pasting.
2) Sealing by Hot Melting Material
Thermally fusing hot melting material and supplying it to a paper to be sealed while it is not cooled and solidified, it is troublesome since it is required to establish means and method to maintain it not solidified until it fully adheres to the paper to be used.
3) Laminated Polyethylene
The price of polyethylene as raw material is lowest among plastic resinous materials to be used and is easy for handling and it is ready for operation since it adheres to the paper only by blowing hot air of about 300 .degree. C., and further it immediately solidifies after stopping a hot air blast. Sealing by glue and hot melt can be made by applying sealing material only for the portion to be sealed, but the method of sealing by laminated polyethylene paper and laminated polyethylene are applied by adhesion roll and then cooled, so it is required to apply on the all surfaces of the paper, but the polyethylene has large water proofing and heat resistant property it has been desired for use as drink cups from the point of production speed and its efficiency.